Where's my other FastRam?

[AmiDude]

There's a FastRAM problem with my A2500.
I've got a A2630 accelerator card with 4Mb,
and a GVP Impact A2000-HC+8 seriesII with 8MB on it.
But the system recognizes only 8MB fast instead of
12MB + 1MB chip. Where's the other 4MB fastram???
:-?
I tried different jumper settings, but can't get the
full 12MB fast-ram to work. What's wrong with it?
Anyone knows how to solve this problem?
:-?

EDIT:
B.T.W. the A2500 has the same motherboard as the A2000.
In this case rev. 6.2.

[AmiDude]

@Lemmink

I didn't know that. What's the difference then
between the A2630 and other accelerators you
mentioned? I mean: is the A2630 not a "real"
accelerator?

 :-)

[AmiDude]

@Lemmink

Thanks for explaining that. The reason why I use
an A2630 is that it was standard equiped with
the A2500. I wanted to keep the A2500 as original
as possible, and yes, I'm a collector, but I
replaced the A2091 with the GVP and I've installed
a ROM 2.05(37.500) with WB OS2.1 on the HD.

 :-)